Checkpoint duration too long at times
Environment:
Informix Dynamic Server 7.31 UD2 R1
HP-UX 11.0
As you can see below
10:44:50 Checkpoint Completed: duration was 0
seconds.
10:59:59 Checkpoint Completed: duration was 0
seconds.
11:15:08 Checkpoint Completed: duration was 0
seconds.
11:30:17 Checkpoint Completed: duration was 0
seconds.
11:45:26 Checkpoint Completed: duration was 0
seconds.
12:00:53 Checkpoint Completed: duration was 19
seconds.
12:16:02 Checkpoint Completed: duration was 0
seconds.
12:31:34 Checkpoint Completed: duration was 23
seconds.
12:46:44 Checkpoint Completed: duration was 0
seconds.
13:01:54 Checkpoint Completed: duration was 1
seconds.
13:17:05 Checkpoint Completed: duration was 2
seconds.
13:32:15 Checkpoint Completed: duration was 0
seconds.
13:47:24 Checkpoint Completed: duration was 0
seconds.
14:02:33 Checkpoint Completed: duration was 1
seconds.
14:17:43 Checkpoint Completed: duration was 1
seconds.
14:32:54 Checkpoint Completed: duration was 0
seconds.
14:48:03 Checkpoint Completed: duration was 0
seconds.
15:03:13 Checkpoint Completed: duration was 2
seconds.
15:18:23 Checkpoint Completed: duration was 0
seconds.
15:35:08 Checkpoint Completed: duration was 97
seconds.
we have at times checkpoints of duration more than a
minute. This is totally unacceptable in production
environment.
We are unable to diagnose a pattern for this. It could
happen at any time throughout the day. I don't have
any clues where to look for and what could be the
possible reason for this behaviour.
Here are the related checkpoint parameters which we
have set in our environment for your reference.
MULTIPROCESSOR 1 # 0 forsingle-processor, 1 for multi-processor
NUMCPUVPS 5 # Number of user (cpu)vps
SINGLE_CPU_VP 0
BUFFERS 500000
CLEANERS 128
CKPTINTVL 900
LRUS 128
LRU_MAX_DIRTY 2
LRU_MIN_DIRTY 1
Also interesting most of the times we have 0 LRU
writes in the system and only writes happen are the
chunkwrites at the time of checkpoint.
Fg Writes LRU Writes Chunk Writes
0 2 14620
Are we hitting some kind of bug? Or doing something
wrong.
Any help on this is highly appreciated.
Do let me know if you need more information.
Thanks and regards,
Vineet
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